I always wonder how people know things like that. It's like asking "how does it feel to have your face run over by a lawn mower?" The only guy who knows is the guy who can't tell you... because he's dead

One fairly common use for benzaldehyde is to make benzoic acid. The sodium salt is sodium benzoate, a food preservative in almost every low pH prepared food (including soda).

In a school teaching lab it can be used as an example of an aldehyde that makes wonderful 2,4-DNP crystals and beautiful silver mirrors (Tollen's test) but does not give an iodoform reaction. The carbonyl is present (by IR test) but it is different in position from ketones and carboxylic acids. It can be oxidized to benzoic acid in one lab session and recrystallized in another demonstrating a common chemical transformation and a useful purification methodology. It is fairly non-toxic, always a plus, so is appropriate for use in a lab full of first time organic chemists. It has a UV chromophore enabling its use to demonstrate thin layer chromatography with UV visualization (vs iodine or acid char - DANGEROUS!). And it smells nice and won't empty out the building in the event of a spill.